1. Field of the Invention
The present invention generally relates to an excess flow check valve which permits fluid flow through a flow line when the flow is below a predetermined flow rate but closes the flow line if the flow rate rises above the predetermined limit to prevent uncontrolled flow or discharge of fluids such as might occur if a fluid line is ruptured. More specifically, the present invention relates to the packaging or mounting of an excess flow check valve in a capsule to facilitate its installation in various flow lines, fittings, pipe systems, appliances and the like. The excess flow valve is magnetically operated in response to a low differential pressure with the packaging being in the form of a self contained capsule which can be inserted in various flow passageways including a valve body, a connector fitting, a hose fitting, a pipe nipple, a tube, an appliance and other similar installations to provide excess flow protection. The capsule facilitates assembly of the individual components into a self contained compact package, provides for easy insertion of the capsule into a fitting or tube, provides means for substantially restricting flow, provides means for allowing small leakage flow for automatic valve resetting, precisely positions and retains the components of the valve for proper operation, provides a unique structure for coupling the two capsule components, permits flow testing as a capsule to verify performance and provides a compact configuration to minimize the size, diameter and length required to accommodate the capsule.
2. Description of the Prior Art
Prior Pat. No. 2,569,316 issued Sep. 25, 1951 to Jerman discloses a differential pressure check valve which prevents excess flow which uses magnetic attraction to retain the valve member in "open" position. My prior Pat. No. 4,874,012 issued Oct. 17, 1989 discloses a magnetically operated excess flow valve for low differential pressure application such as for natural gas appliances. As illustrated in the above mentioned prior patents, the components of the flow valve are necessarily assembled when being installed at a site of use. The necessity of assembling the components with respect to a pipe fitting or other flow line is quite time consuming, requires considerable manual dexterity and introduces the possibility of erroneous or malfunctioning installations. The prior art does not disclose the concept of packaging the components of a low differential pressure magnetically operated excess flow valve in a capsule to facilitate its installation at a site of use.